After graduating from the University of California, Shimamoto entered the mortgage industry.But after the subprime-mortgage market crashed in 2007 he "jumped from bank to bank."

"In my spare time, I would go and eat ramen around Los Angeles," he says. "It made me think that maybe I needed a career change."

He started a blog, Go Ramen, about his journey, in 2007. Two years later he moved to Tokyo on a mission to become a ramen expert.

"I didn't know if I was going to own a ramen shop, or become a big-time chef," he says. "But I knew that I had to do something (related to) ramen."

Tokyo calling

Shimamoto spent four years in Tokyo, managing three different ramen shops. During this time he also took a month off work to travel, making his way from Hokkaido, the northernmost Japanese island, to Kyushu, all the way down south.

"I once had 55 bowls of ramen in 28 days, in 21 different cities. That kind of changed my perspective of what ramen was like," herecalls.

Within the space of a year, Shimamoto had eaten some 600 bowls of ramen. His favorite? Tokyo-style shoyu ramen, which has a soup base flavored with soy sauce.

"There's a nostalgic aspect to it. It was the first ramen I had ever eaten as a kid in Tokyo," he says.

"It always takes me back to the same place. That clean shoyu chicken, and light broth."

With the recipe perfected, Shimamoto posted about his new creation on his blog a few days before the ramen burger debuted at Smorgasburg.

It went viral.

"The night before Smorgasburg, (the TV show) Good Morning America called and said they wanted to put me on the morning show that day -- before we sold the burger.

"It was a crazy time."

The burger sold for $8 a pop at the food market and was a runaway success.

Ramen dreams

Shimamoto's noodle creationbecame a mainstay at Smorgasburg and its success spawned similarventures around the world.

He says he's heard of ramen burgers popping up in Canada, Australia, the Philippines, Singapore and Germany.

But he doesn't own the rights to those recipes.

"It's very difficult to patent a recipe," he says. "I didn't see a point in paying for trademark fees. It's flattering that people copy it ... it doesn't hurt me at all."

His goal, he says, is to make quality ramen andshare it around the world.

The chef-inventor's latest restaurant, Ramen Shack, opened in New York in September 2016. Located in Long Island City, Queens, the restaurant offers a dozen types of ramen -- including, of course, the burger that propelled him to fame.

There is also a teriyaki pulled porkburger that's topped with yuzu coleslaw and teriyaki sauce.

"This is where I get to showcase what I can do with my ingredients," he tells CNN. "It's really just me testing and learning about ramen every day. Making something new, then creating it into the perfect bowl for customers."

He also runs a wholesale business, making ramen soups and ingredients -- such as toppings -- for other shops and restaurants.

Previously, Shimamoto ran now-defunct restaurant, Ramen Co. in New York City, which had an outpost in Los Angeles.

"Because of the ramen burger I was able to build separate businesses that have taken my dream a step forward."

Ramen is life

The ramen burger reflects Shimamoto's journey as a Japanese-American.

"The two cultures I grew up in feed into the type of food I've been making," he says. "I'm trying to make food that tickles my memories, and my childhood."

"Ramen Shack is ramen from my own personality," he explains. "When people come to eat it, they taste my experience -- the different bowls I've learned (about) over the years,and how my passion has turned into a bowl of ramen."